A: Sagui, there is a lot of talk about preventing DVT, or deep venous thrombosis, in adults. However, it has not been a significant issue for children.

DVT occurs when a blood clot forms in a deep vein in the body, often in the legs. Overall, it affects 2 to 3 percent of adults, mostly people with medical conditions that decrease blood flow and increase clotting in the blood. DVT is most common in people who are elderly, overweight or post-surgery; those who have varicose veins, heart failure or cancer; and women who are pregnant or on oral contraceptives or hormone treatment.

DVT is rare in children. It's only one-tenth as common as in adults. The rare cases of DVT in children occur mostly in hospitalized children who have cancer, fractures and orthopedic procedures, serious infections, blood clotting problems and catheters staying in their veins.

The symptoms of DVT are pain, swelling and redness in the tissue surrounding the clot. Occasionally, clots can break off and travel to the heart and lungs, leading to a pulmonary embolism (blood clot in the lungs), which could be fatal. For this reason it's important to do everything possible to prevent DVT, and recognize and treat it promptly when it occurs.

DVT has been found to be more common in adults taking long flights, probably due to being immobilized and a little dehydrated. Studies have found DVT in less than one in a million air travelers. While flights longer than eight hours have four times increased risk of DVT, the chance of getting DVT on a long flight is still less than 1 percent. Recommendations to prevent DVT in adults on long flights include moving your feet and massaging your legs in your seat, getting up and walking around periodically, and drinking plenty of fluids. Adults with medical conditions that put them at risk for DVT should consult their doctor about specific recommendations, which might include wearing special elastic socks and taking anti-coagulant medication. You should talk with your own doctor about precautions to prevent another DVT.

Since DVT is so rare in healthy children, there are no specific recommendations for your baby's flight. However, to be safe, you could periodically massage your baby's legs, walk her around a little and be sure to give her plenty of fluids on the flight.